Sherlock's new friend

This is about Samantha Watson, she has lived in London all her life and one fatal day she lost her mother and father in a fire and she was sent to live with her Uncle John Watson. John was her favorite in the family and she loved him so much, but when she goes to live with her Uncle at 221B Baker street she didn't know that her uncle had a flat mate named Sherlock Holmes, She learned to really like Sherlock even though he could be quite rude. She liked Sherlock and soon Sherlock began to like her as well. Does it seem true that Sherlock could have a new friend or could it just be pure sympathy? (In this story Samantha or Sam is 14 years old but even at that age she is very good at helping out with cases and being a little detective.)